Underweight in the First 2 Years of Life and Growth in Later Childhood
Authors: Courtney A. South, Charles D. G. Keown-Stoneman, Catherine S. Birken, Vasanti S. Malik, Stanley H. Zlotkin, Jonathon L. Maguire, Catherine Birken, Jonathon Maguire, Christopher Allen, Laura Anderson, Dana Arafeh, Mateenah Jaleel, Charles Keown-Stoneman, Natricha Levy McFarlane, Jessica Omand, Mary Aglipay, Imaan Bayoumi, Cornelia Borkhoff, Sarah Carsley, Katherine Cost, Curtis D'Hollander, Anne Fuller, Laura Kinlin, Patricia Li, Pat Parkin, Nav Persaud, Izabela Socynska, Shelley Vanderhout, Leigh Vanderloo, Peter Wong, Xuedi Li, Michelle Mitchell, Hakimat Shaibu, Yulika Yoshida-Montezuma, Marivic Bustos, Pamela Ruth Flores, Martin Ogwuru, Sharon Thadani, Julia Thompson, Laurie Thompson, Kardelen Kurt, Ataat Malick, Jennifer Batten, Jennifer Chan, John Clark, Maureen Colford, Amy Craig, Kim De Castris-Garcia, Sharon Dharman, Anthony Garcia, Sarah Kelleher, Sandra Marquez, Salimah Nasser, Tammara Pabon, Michelle Rhodes, Rafael Salsa, Jia Shin, Julie Skelding, Daniel Stern, Kerry Stewart, Erika Sendra Tavares, Shannon Weir, Maria Zaccaria, Magdalena Janus, Eric Duku, Caroline Reid-Westoby, Patricia Raso, Amanda Offord, Emy Abraham, Sara Ali, Kelly Anderson, Gordon Arbess, Jillian Baker, Tony Barozzino, Sylvie Bergeron, Gary Bloch, Joey Bonifacio, Ashna Bowry, Caroline Calpin, Douglas Campbell, Sohail Cheema, Elaine Cheng, Brian Chisamore, Evelyn Constantin, Karoon Danayan, Paul Das, Viveka De Guerra, Mary Beth Derocher, Anh Do, Kathleen Doukas, Anne Egger, Allison Farber, Amy Freedman, Sloane Freeman, Sharon Gazeley, Karen Grewal, Charlie Guiang, Dan Ha, Curtis Handford, Laura Hanson, Leah Harrington, Sheila Jacobson, Lukasz Jagiello, Gwen Jansz, Paul Kadar, Lukas Keiswetter, Tara Kiran, Holly Knowles, Bruce Kwok, Piya Lahiry, Sheila Lakhoo, Margarita Lam-Antoniades, Eddy Lau, Denis Leduc, Fok-Han Leung, Alan Li, Roy Male, Aleks Meret, Elise Mok, Rosemary Moodie, Katherine Nash, James Owen, Michael Peer, Marty Perlmutar, Navindra Persaud, Andrew Pinto, Michelle Porepa, Vikky Qi, Noor Ramji, Danyaal Raza, Katherine Rouleau, Caroline Ruderman, Janet Saunderson, Vanna Schiralli, Michael Sgro, Hafiz Shuja, Farah Siam, Susan Shepherd, Cinntha Srikanthan, Carolyn Taylor, Stephen Treherne, Suzanne Turner, Fatima Uddin, Meta van den Heuvel, Thea Weisdorf, John Yaremko, Ethel Ying, Elizabeth Young, Michael Zajdman, Peter Juni, Gurpreet Lakhanpal, Gerald Lebovic, Audrey Stitt, Kevin Thorpe, Ifeayinchukwu (Shawn) Nnorom, Esmot ara Begum, Rita Kandel, Michelle Rodrigues, Andrea Djolovic, Raya Assan, Homa Bondar
Journal: JAMA Network Open (2022)

Few studies have examined the association between underweight in the first 2 years and growth in later childhood in high-income countries.To evaluate the associations of underweight in the first 2 years of life with body mass index (calculated as weight in kilograms divided by height in meters squared) z score (zBMI), weight-for-age z score (WAZ), and height-for-age z score (HAZ) from ages 2 to 10 years.This prospective cohort study was conducted between February 2008 to September 2020 in The Applied Research Group for Kids! practice-based research network in Toronto, Canada. Participants included healthy children aged 0 to 10 years. Data were analyzed from October 2020 to December 2021.Underweight (ie, zBMI less than -2, per the World Health Organization) in the first 2 years of life.The primary outcome was zBMI from ages 2 to 10 years. Linear mixed-effects models were used to account for multiple growth measures over time.A total of 5803 children were included in the primary analysis. At baseline, the mean (SD) age was 4.07 (5.62) months, 2982 (52.2%) were boys, and 550 children (9.5%) were underweight. Underweight in the first 2 years was associated with lower zBMI (difference, -0.39 [95% CI, -0.48 to -0.31]) at 10 years and lower HAZ (difference, -0.24 [95% CI, -0.34 to -0.14]) at age 2 years. Stratified by sex, at age 10 years, girls and boys with underweight in the first 2 years both had lower zBMI (girls: difference, -0.47 [95% CI, -0.59 to -0.34]; boys: difference, -0.32 [95% CI, -0.44 to -0.20]). At age 10 years, children with underweight and a lower zBMI growth rate in the first 2 years had lower zBMI (difference, -0.64 [95% CI, -0.77 to -0.53) and HAZ (difference, -0.12 [-0.24 to -0.01]), while children with underweight and a higher zBMI growth rate in the first 2 years had similar zBMI (difference, -0.11 [95% CI, -0.22 to 0.001]) and higher HAZ (difference, 0.16 [95% CI, 0.05 to 0.27]) compared with children who did not have underweight in the first 2 years.In this prospective cohort study, children with underweight in the first 2 years of life had lower zBMI and HAZ in later childhood. These associations were attenuated among children with a higher growth rate in the first 2 years.